Agrobacterium rhizogenes is a soil bacteria that is known to infect wounded root tissue and that transfers a portion of its bacterial plasmid, the Ri plasmid, to the plant. The Ri-T-DNA that is transferred to the plant induces the formation of adventitious roots and these genetically transformed roots can be regenerated into whole plants that transmit the Ri T-DNA to their progeny. Agrobacterium rhizogenes has, therefore, been used to generate stably transformed whole plants. In one application of this technology, secondary metabolites can be produced from culture using this method.
With the advent of genomics-based discovery of genes and genetic elements, new methods are needed to facilitate the rapid screening of the large numbers of genes (or genetic elements) that are becoming available. Typically, genes of interest are cloned and then stably transformed using Agrobacterium tumefaciens mediated delivery or by a particle gun method into plants for functional analysis of the gene or genetic element. This method can take up to 9 months for transgenic plants, such as soybean, to be transformed and ready for testing. This is a slow and inefficient process. Therefore, there is a need for a rapid method of screening large numbers of genes and gene constructs in planta for functionality.